Two known methods to give synthetic resin anti-static character are mixing of an anti-static agent in the resin by kneading and applying an anti-static agent to the surface of the resin. Because the former is not effective for polystyrene resin, ABS or melamine resin, the latter is generally adopted for these resins. The anti-static agent which is used in the latter method is called an external anti-static agent. Surfactants are generally used as an external anti-static agent. The anti-static agent which is applied to the resin used for food packaging should be suitable for ingestion and excellent in supplying anti-static character.